Nikon Coolpix S6300 Long Shutter Problem

It takes fireworks mode with only ~1 s shutter time, instead of 4 s that is in the specifications on the official site:http://europe-nikon....;/coolpix-s6300Under specifications: "Speed: ... 4 s (Fireworks show scene mode)"

I have made a video about my problem:

Edit: I made a test in the dark, with a laser pointers light on the wall: